Biological Treatment Systems for Fish Processing Wastewater - A Review

Abstract

Processing of fish involves mainly the application of various preservation techniques for retaining a superior quality and enhancing shelf life. It also covers aspects like value-addition to produce a wide variety of products. But during these fish processing operations large quantity of effluents, which contain active microorganisms in various forms are being generated. Depending on the processing operation involved, the level of contamination varies. This high-strength wastewater from fish processing industry is of great concern world-wide and hence recently stringent liquid effluent policies are being adopted. A number of treatment strategies at different levels are applicable for reducing this risk, however biological treatment is one of the best options for fish processing wastewater, rich in organic matter. Biological treatment includes both aerobic and anaerobic processes. Aerobic processes such as activated sludge, lagoons, trickling filter and rotating biological contactor are suitable for organics removal. The anaerobic processes can also remove 80-90% organics and produce biogas. A combination of both anaerobic digestion and aerobic process is regarded as an effective approach to reduce the contaminants in fish processing wastewater.